Waste gas leakage preventive device in the basic oxygen furnace

ABSTRACT

A movable cylindrical shield is slidably mounted on the lower end of a hood over the open end of a converter and cooperates with fluent filled channels to provide a gas tight seal. In action, suction pipes are provided to collect any gas which is not collected by the hood.

United States Patent [72] Inventors Yasuhiro Yagi Okayama-shi MasashiKawana, Kurashiki-shi Takashi Kosukegawa, Okayama-shi, Japan [2l l Appl.No. 765,606 [22] Filed Oct. 7, 1968 [45] Patented Jan. 26, 1971 {73}Assignee Kawasaki Steel Corporation and Kawasaki Dockyard Co., Ltd.

[54] WASTE GAS LEAKAGE PREVENTIVE DEVICE IKN THE BASIC OXYGEN F URNACE 4Claims, 5 Drawing Figs.

[52] U.S. CI 266/15, 266/36 [5l] InLCl C21cS/40 [50] Field of Search266/35, 36,

[56] References Cited UNITED STATES PATENTS 3,170,017 2/1965 Namy266/36X 3,325,160 6/1967 Eklund 266/36X 3,358,983 12/1967 Wegscheider etal 266/35 3,372,917 3/1968 Richardson 266/15 Primary Examiner-Frank T.Yost Attorney-Sughrue, Rothwell, Mion, Zinn & MacPeak ABSTRACT: Amovable cylindrical shield isslidably mounted on the lower end of a hoodover the open end of a converter and cooperates with fluent filledchannels to provide a gas tight seal. In action, suction pipes areprovided to collect any gas which is not collected by the hood. i

PATENTEU m26 |911 SHEET 2 UF 2 FIG. 4

FIG. 3

WASTE GAS LEAKAGE PREVENTIVE DEVICE IN THE BASIC OXYGEN FURNACE Thepresent invention relates to an improvement of the hood portion of thebasic oxygen furnace having a device for recovering the waste gas fromthe converter in imperfect com bustion condition.

A waste gas recovering device for a converter is well known and capturesthe gas exhausted out of the converter, so that it may not be mixed withthe atmosphere, by controlling the gas pressure in the hood, recoversthe gas into a gas holder after cooling and dusting the gas, andutilizes the recovered gas for fuel, chemical material and the like.

Since the portion between the furnace port and the hood portion cannotbe perfectly shielded because of the accumulation of the slag spoutedout of the furnace and since the converter must be inclined when thesteel is removed therefrom and when material is put in, as well as theimperfect controlling of the gas pressure`in the hood corresponding tothe large variation of the gas pressure in the converter, waste gas,including smoke, leaks out of the portion between the furnace port andhood portion. This leakage of the waste gas also passes out of theconverter building into the open air and causes an undesirableenvironment from a view point of public nuisances. The present inventionis to solve these problems by capturing the waste gas.

In the prior art, a device was provided for preventing the smoke and gasfrom leaking out of the converter, for instance as shown in FIG. I, butin this device the bottom portion could not be separated. ln thisconstruction a part of hood portion b is made demountable from thefurnace port a for putting in brick and a heat shield f is disposedaround the lower hood d which is ordinarily fixed to the floor c forpreventing the smoke and gas from leaking upward. The upper hood econnected to said lower hood d is demountable. There are also devicesknown for capturing the leaking waste gas from between an inner cylinderand outer cylinder wherein the hood is made of a double construction andthe waste gas is captured through the inner cylinder. In the formerdevice it is difficult to take brick into the furnace for it isimpossible to lower the floor c because of the fixed lower hood portiond. ln the latter device the structure .of the hood becomes complicatedbecause of the accessories attached to the hood portion.

It is an object of the present invention to provide a device forpreventing the waste gas from leaking out of the basic oxygen furnace.

The subject matter of the present invention consists in a waste gasleakage preventing device in the basic oxygen furnace comprising ashielding plate fixed to the lower portion of a vertically movablecylinder mounted on the lower end of the waste gas recovering hood ofthe basic oxygen furnace, a shield box in which the lower end of saidshielding plate extends disposed on the brick take-in floor near thefurnace port or on the heat proof plate, and a leaking waste gascapturing pipe disposed downwardly of said shield box.

The invention will be better understood by the following descriptiontaken in conjunction with the accompanying drawings in which:

FIG. l is schematic view showing a conventional structure of a waste gasrecovering hood portion of a converter;

FIG. 2 is a front elevation view partly in section of the waste gasleakage preventive device of the basic oxygen furnace in accordance withthe present invention;

FIG. 3 is a side view of the same;

FIG. 4 is a plan view of the leaking waste gas capturing pipe of thesame; and

FIG. 5 is a schematic view showing another embodiment of the preventivedevice in accordance with the present invention.

Referring to FIG. 2 showing an embodiment of the present invention, avertically movable cylinder 3 is slidably mounted on the lower end ofthe waste gas recovering hood 2 of the basic oxygen furnace. The upperend of said cylinder 3 is bent inward so that the edge l2 of the bentend faces a shield box l0 disposed at the lower end of said waste gasrecovering hood 2. A shielding plate 6 is mounted on the lower end ofsaid cylinder 3 so that the lower end 13 of said shielding plate 6extending downwardly faces a shield box 5 disposed on the brick take-infloor 4 in the vicinity of furnace port 1l inwardly of the heat shield 8of the basic oxygen furnace 1, whereby said edge I2 of the bent end ofsaid cylinder 3 and said lower end I3 of said shielding plate 6 arebrought into said shield boxes l0 and 5, respectively. The shield boxesare formed into rain gutterlike boxes upwardly open and are filled withpowder such as sand or liquid such as water for sealing. When the edgel2 of the bent end of said elevating cylinder and lower end I3 of saidshielding plate 6 are brought into these shield boxes 10,5, the shieldboxes completely prevent the gas within the furnace from leakingtherefrom. Leaking waste gas capturing pipes 9 are provided under theshield box 5. From the capturing pipes 9, branch pipes l5 are extendedinwardly from both sides thereof and sufficiently draw the vleakingwaste gas toward these pipes. The capturing pipes 9 may be pipesprovided with a plurality of suction holes on the pipe wall thereof. lnthe embodiment shown in FIG. 2 the capturing pipes 9 are disposed on theunderside of the floor 4 for the leaking gas spreads downwardly from thefloor 4 on which the shield box 5 is disposed, and in another embodimentshown in FIG. 5 the capturing pipes 9 are disposed within the heatshield 16 below the shield box 5 which also disposed on the heat shield16. The converter must be inclined forward when the material is puttherein. That is, as the converter must be inclined rightward in FIG. 3,the brick take-in floor 4 is provided with a cutout portion I4 so thatthe converter maybe operated and inclined without trouble. Therefore, inthe front part of the convener, said leakage preventive device cannot bemounted thereto. However, another waste gas capturing pipe 7 is disposedat the upper portion of the front side of the converter for the purposeof capturing the waste gas produced when the molten iron is put into theconverter.

According to the construction as described above, the waste gas issucked into the waste gas recovering hood 2 by controlling the pressurewithin the hood 2 after the cylinder 3 is moved down along the waste gasrecovering hood 2 to the position where the edge l2 of the bent end ofthe cylinder and the lower end I3 of the shielding plate 6 are broughtinto the shield boxes 10 and 5. But in case the pressure is notperfectly controlled in response to the variation of conditions in theconverter, the waste gas leaks out of the furnace port and spread allover under the brick take-in floor 4. In such case, the leaking wastegas is sucked through openings of the capturing pipes 9 extending underthe shield box 5 so that the smoke will not spread over the converter orup to the working floor. The leaking waste gas flowing out forwardlyfrom the converter is easily sucked upwardly by the capturing pipe 7.

In accordance with the present invention, the waste gas leaking out ofthe converter between the waste gas recovering hood 2 and the furnaceport 1I is almost completely captured, and problems affecting theenvironment are simply solved. Moreover, since the brick take-infloor 4can be disposed near the furnace port Il, the work involving handling ofthe brick is simplified.

We claim:

1. A waste gas leakage preventing device for a basic oxygen furnace ofthe type having an upwardly open, horizontally tiltable vessel partiallysurrounded by a heat shield having a floor portion disposed adjacent theuppermost end thereof comprising a vertically extending cylindrical hoodmeans disposed in spaced vertical relation to said vessel, a verticallymovable cylinder slidably mounted on said hood member, shield box meansmounted on said hood means and on said heat shield below the top of saidvessel for cooperating with the edges of said cylinder to provide a gastight hood extenmeans to provide access into said vessel.

4. A device as set forth in claim l wherein said shield box means arecomprised of upwardly open annular channels adapted to be filled with afluent material for cooperation with said cylinder, the upper end ofsaid cylinderbeing turned inwardly and downwardly for cooperation withits respective shield boxv means.

2. A device as set forth in claim 1 further comprising suction pipemeans disposed below said shield box means mounted on said heat shield.3. A device as set forth in claim 2 further comprising additionalsuction pipe means disposed adjacent said cylinder and above said vesselon the side thereof not surrounded by said heat shield.
 4. A device asset forth in claim 1 wherein said shield box means are comprised ofupwardly open annular channels adapted to be filled with a fluentmaterial for cooperation with said cylinder, the upper end of saidcylinder being turned inwardly and downwardly for cooperation with itsrespective shield box means.